I’ve tried and follows install the “How to track error pages (404 pages) in Piwik?”-solution.
This doesn’t work with my CMS, because my error-page doesnt show at url. It does not create a path how “excample.org/404.html”, its only show the wrong url and the browsertitle switched to this: “404 error - Sitename” (and the content is from my error-default in the backend from my cms).